/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

#include "uv.h"
#include "internal.h"

#include <stddef.h> /* NULL */
#include <stdio.h> /* printf */
#include <stdlib.h>
#include <string.h> /* strerror */
#include <errno.h>
#include <assert.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <limits.h> /* INT_MAX, PATH_MAX, IOV_MAX */
#include <sys/uio.h> /* writev */
#include <sys/resource.h> /* getrusage */
#include <pwd.h>

#ifdef __linux__
#include <sys/ioctl.h>
#endif

#ifdef __sun
#include <sys/types.h>
#include <sys/wait.h>
#endif

#ifdef __APPLE__
#include <mach-o/dyld.h> /* _NSGetExecutablePath */
#include <sys/filio.h>
#include <sys/ioctl.h>
#if defined(O_CLOEXEC)
#define UV__O_CLOEXEC O_CLOEXEC
#endif
#endif

#if defined(__FreeBSD__) || defined(__DragonFly__)
#include <sys/sysctl.h>
#include <sys/filio.h>
#include <sys/ioctl.h>
#include <sys/wait.h>
#define UV__O_CLOEXEC O_CLOEXEC
#if defined(__FreeBSD__) && __FreeBSD__ >= 10
#define uv__accept4 accept4
#define UV__SOCK_NONBLOCK SOCK_NONBLOCK
#define UV__SOCK_CLOEXEC SOCK_CLOEXEC
#endif
#if !defined(F_DUP2FD_CLOEXEC) && defined(_F_DUP2FD_CLOEXEC)
#define F_DUP2FD_CLOEXEC _F_DUP2FD_CLOEXEC
#endif
#endif

#ifdef _AIX
#include <sys/ioctl.h>
#endif

#if defined(__ANDROID_API__) && __ANDROID_API__ < 21
#include <dlfcn.h> /* for dlsym */
#endif

static int uv__run_pending(uv_loop_t* loop);

/* Verify that uv_buf_t is ABI-compatible with struct iovec. */
STATIC_ASSERT(sizeof(uv_buf_t) == sizeof(struct iovec));
STATIC_ASSERT(sizeof(&((uv_buf_t*)0)->base) == sizeof(((struct iovec*)0)->iov_base));
STATIC_ASSERT(sizeof(&((uv_buf_t*)0)->len) == sizeof(((struct iovec*)0)->iov_len));
STATIC_ASSERT(offsetof(uv_buf_t, base) == offsetof(struct iovec, iov_base));
STATIC_ASSERT(offsetof(uv_buf_t, len) == offsetof(struct iovec, iov_len));

uint64_t uv_hrtime(void)
{
    return uv__hrtime(UV_CLOCK_PRECISE);
}

void uv_close(uv_handle_t* handle, uv_close_cb close_cb)
{
    assert(!(handle->flags & (UV_CLOSING | UV_CLOSED)));

    handle->flags |= UV_CLOSING;
    handle->close_cb = close_cb;

    switch (handle->type) {
    case UV_NAMED_PIPE:
        uv__pipe_close((uv_pipe_t*)handle);
        break;

    case UV_TTY:
        uv__stream_close((uv_stream_t*)handle);
        break;

    case UV_TCP:
        uv__tcp_close((uv_tcp_t*)handle);
        break;

    case UV_UDP:
        uv__udp_close((uv_udp_t*)handle);
        break;

    case UV_PREPARE:
        uv__prepare_close((uv_prepare_t*)handle);
        break;

    case UV_CHECK:
        uv__check_close((uv_check_t*)handle);
        break;

    case UV_IDLE:
        uv__idle_close((uv_idle_t*)handle);
        break;

    case UV_ASYNC:
        uv__async_close((uv_async_t*)handle);
        break;

    case UV_TIMER:
        uv__timer_close((uv_timer_t*)handle);
        break;

    case UV_PROCESS:
        uv__process_close((uv_process_t*)handle);
        break;

    case UV_FS_EVENT:
        uv__fs_event_close((uv_fs_event_t*)handle);
        break;

    case UV_POLL:
        uv__poll_close((uv_poll_t*)handle);
        break;

    case UV_FS_POLL:
        uv__fs_poll_close((uv_fs_poll_t*)handle);
        break;

    case UV_SIGNAL:
        uv__signal_close((uv_signal_t*)handle);
        /* Signal handles may not be closed immediately. The signal code will */
        /* itself close uv__make_close_pending whenever appropriate. */
        return;

    default:
        assert(0);
    }

    uv__make_close_pending(handle);
}

int uv__socket_sockopt(uv_handle_t* handle, int optname, int* value)
{
    int r;
    int fd;
    socklen_t len;

    if (handle == NULL || value == NULL)
        return -EINVAL;

    if (handle->type == UV_TCP || handle->type == UV_NAMED_PIPE)
        fd = uv__stream_fd((uv_stream_t*)handle);
    else if (handle->type == UV_UDP)
        fd = ((uv_udp_t*)handle)->io_watcher.fd;
    else
        return -ENOTSUP;

    len = sizeof(*value);

    if (*value == 0)
        r = getsockopt(fd, SOL_SOCKET, optname, value, &len);
    else
        r = setsockopt(fd, SOL_SOCKET, optname, (const void*)value, len);

    if (r < 0)
        return -errno;

    return 0;
}

void uv__make_close_pending(uv_handle_t* handle)
{
    assert(handle->flags & UV_CLOSING);
    assert(!(handle->flags & UV_CLOSED));
    handle->next_closing = handle->loop->closing_handles;
    handle->loop->closing_handles = handle;
}

int uv__getiovmax(void)
{
#if defined(IOV_MAX)
    return IOV_MAX;
#elif defined(_SC_IOV_MAX)
    static int iovmax = -1;
    if (iovmax == -1) {
        iovmax = sysconf(_SC_IOV_MAX);
        /* On some embedded devices (arm-linux-uclibc based ip camera),
     * sysconf(_SC_IOV_MAX) can not get the correct value. The return
     * value is -1 and the errno is EINPROGRESS. Degrade the value to 1.
     */
        if (iovmax == -1)
            iovmax = 1;
    }
    return iovmax;
#else
    return 1024;
#endif
}

static void uv__finish_close(uv_handle_t* handle)
{
    /* Note: while the handle is in the UV_CLOSING state now, it's still possible
   * for it to be active in the sense that uv__is_active() returns true.
   * A good example is when the user calls uv_shutdown(), immediately followed
   * by uv_close(). The handle is considered active at this point because the
   * completion of the shutdown req is still pending.
   */
    assert(handle->flags & UV_CLOSING);
    assert(!(handle->flags & UV_CLOSED));
    handle->flags |= UV_CLOSED;

    switch (handle->type) {
    case UV_PREPARE:
    case UV_CHECK:
    case UV_IDLE:
    case UV_ASYNC:
    case UV_TIMER:
    case UV_PROCESS:
    case UV_FS_EVENT:
    case UV_FS_POLL:
    case UV_POLL:
    case UV_SIGNAL:
        break;

    case UV_NAMED_PIPE:
    case UV_TCP:
    case UV_TTY:
        uv__stream_destroy((uv_stream_t*)handle);
        break;

    case UV_UDP:
        uv__udp_finish_close((uv_udp_t*)handle);
        break;

    default:
        assert(0);
        break;
    }

    uv__handle_unref(handle);
    QUEUE_REMOVE(&handle->handle_queue);

    if (handle->close_cb) {
        handle->close_cb(handle);
    }
}

static void uv__run_closing_handles(uv_loop_t* loop)
{
    uv_handle_t* p;
    uv_handle_t* q;

    p = loop->closing_handles;
    loop->closing_handles = NULL;

    while (p) {
        q = p->next_closing;
        uv__finish_close(p);
        p = q;
    }
}

int uv_is_closing(const uv_handle_t* handle)
{
    return uv__is_closing(handle);
}

int uv_backend_fd(const uv_loop_t* loop)
{
    return loop->backend_fd;
}

int uv_backend_timeout(const uv_loop_t* loop)
{
    if (loop->stop_flag != 0)
        return 0;

    if (!uv__has_active_handles(loop) && !uv__has_active_reqs(loop))
        return 0;

    if (!QUEUE_EMPTY(&loop->idle_handles))
        return 0;

    if (!QUEUE_EMPTY(&loop->pending_queue))
        return 0;

    if (loop->closing_handles)
        return 0;

    return uv__next_timeout(loop);
}

static int uv__loop_alive(const uv_loop_t* loop)
{
    return uv__has_active_handles(loop) || uv__has_active_reqs(loop) || loop->closing_handles != NULL;
}

int uv_loop_alive(const uv_loop_t* loop)
{
    return uv__loop_alive(loop);
}

int uv_run(uv_loop_t* loop, uv_run_mode mode)
{
    int timeout;
    int r;
    int ran_pending;

    r = uv__loop_alive(loop);
    if (!r)
        uv__update_time(loop);

    while (r != 0 && loop->stop_flag == 0) {
        uv__update_time(loop);
        uv__run_timers(loop);
        ran_pending = uv__run_pending(loop);
        uv__run_idle(loop);
        uv__run_prepare(loop);

        timeout = 0;
        if ((mode == UV_RUN_ONCE && !ran_pending) || mode == UV_RUN_DEFAULT)
            timeout = uv_backend_timeout(loop);

        uv__io_poll(loop, timeout);
        uv__run_check(loop);
        uv__run_closing_handles(loop);

        if (mode == UV_RUN_ONCE) {
            /* UV_RUN_ONCE implies forward progress: at least one callback must have
       * been invoked when it returns. uv__io_poll() can return without doing
       * I/O (meaning: no callbacks) when its timeout expires - which means we
       * have pending timers that satisfy the forward progress constraint.
       *
       * UV_RUN_NOWAIT makes no guarantees about progress so it's omitted from
       * the check.
       */
            uv__update_time(loop);
            uv__run_timers(loop);
        }

        r = uv__loop_alive(loop);
        if (mode == UV_RUN_ONCE || mode == UV_RUN_NOWAIT)
            break;
    }

    /* The if statement lets gcc compile it to a conditional store. Avoids
   * dirtying a cache line.
   */
    if (loop->stop_flag != 0)
        loop->stop_flag = 0;

    return r;
}

void uv_update_time(uv_loop_t* loop)
{
    uv__update_time(loop);
}

int uv_is_active(const uv_handle_t* handle)
{
    return uv__is_active(handle);
}

/* Open a socket in non-blocking close-on-exec mode, atomically if possible. */
int uv__socket(int domain, int type, int protocol)
{
    int sockfd;
    int err;

#if defined(SOCK_NONBLOCK) && defined(SOCK_CLOEXEC)
    sockfd = socket(domain, type | SOCK_NONBLOCK | SOCK_CLOEXEC, protocol);
    if (sockfd != -1)
        return sockfd;

    if (errno != EINVAL)
        return -errno;
#endif

    sockfd = socket(domain, type, protocol);
    if (sockfd == -1)
        return -errno;

    err = uv__nonblock(sockfd, 1);
    if (err == 0)
        err = uv__cloexec(sockfd, 1);

    if (err) {
        uv__close(sockfd);
        return err;
    }

#if defined(SO_NOSIGPIPE)
    {
        int on = 1;
        setsockopt(sockfd, SOL_SOCKET, SO_NOSIGPIPE, &on, sizeof(on));
    }
#endif

    return sockfd;
}

/* get a file pointer to a file in read-only and close-on-exec mode */
FILE* uv__open_file(const char* path)
{
    int fd;
    FILE* fp;

    fd = uv__open_cloexec(path, O_RDONLY);
    if (fd < 0)
        return NULL;

    fp = fdopen(fd, "r");
    if (fp == NULL)
        uv__close(fd);

    return fp;
}

int uv__accept(int sockfd)
{
    int peerfd;
    int err;

    assert(sockfd >= 0);

    while (1) {
#if defined(__linux__) || (defined(__FreeBSD__) && __FreeBSD__ >= 10)
        static int no_accept4;

        if (no_accept4)
            goto skip;

        peerfd = uv__accept4(sockfd,
            NULL,
            NULL,
            UV__SOCK_NONBLOCK | UV__SOCK_CLOEXEC);
        if (peerfd != -1)
            return peerfd;

        if (errno == EINTR)
            continue;

        if (errno != ENOSYS)
            return -errno;

        no_accept4 = 1;
    skip:
#endif

        peerfd = accept(sockfd, NULL, NULL);
        if (peerfd == -1) {
            if (errno == EINTR)
                continue;
            return -errno;
        }

        err = uv__cloexec(peerfd, 1);
        if (err == 0)
            err = uv__nonblock(peerfd, 1);

        if (err) {
            uv__close(peerfd);
            return err;
        }

        return peerfd;
    }
}

int uv__close_nocheckstdio(int fd)
{
    int saved_errno;
    int rc;

    assert(fd > -1); /* Catch uninitialized io_watcher.fd bugs. */

    saved_errno = errno;
    rc = close(fd);
    if (rc == -1) {
        rc = -errno;
        if (rc == -EINTR)
            rc = -EINPROGRESS; /* For platform/libc consistency. */
        errno = saved_errno;
    }

    return rc;
}

int uv__close(int fd)
{
    assert(fd > STDERR_FILENO); /* Catch stdio close bugs. */
    return uv__close_nocheckstdio(fd);
}

#if defined(__linux__) || defined(__FreeBSD__) || defined(__APPLE__) || defined(_AIX) || defined(__DragonFly__)

int uv__nonblock(int fd, int set)
{
    int r;

    do
        r = ioctl(fd, FIONBIO, &set);
    while (r == -1 && errno == EINTR);

    if (r)
        return -errno;

    return 0;
}

int uv__cloexec(int fd, int set)
{
    int r;

    do
        r = ioctl(fd, set ? FIOCLEX : FIONCLEX);
    while (r == -1 && errno == EINTR);

    if (r)
        return -errno;

    return 0;
}

#else /* !(defined(__linux__) || defined(__FreeBSD__) || defined(__APPLE__) || \
           defined(_AIX) || defined(__DragonFly__)) */

int uv__nonblock(int fd, int set)
{
    int flags;
    int r;

    do
        r = fcntl(fd, F_GETFL);
    while (r == -1 && errno == EINTR);

    if (r == -1)
        return -errno;

    /* Bail out now if already set/clear. */
    if (!!(r & O_NONBLOCK) == !!set)
        return 0;

    if (set)
        flags = r | O_NONBLOCK;
    else
        flags = r & ~O_NONBLOCK;

    do
        r = fcntl(fd, F_SETFL, flags);
    while (r == -1 && errno == EINTR);

    if (r)
        return -errno;

    return 0;
}

int uv__cloexec(int fd, int set)
{
    int flags;
    int r;

    do
        r = fcntl(fd, F_GETFD);
    while (r == -1 && errno == EINTR);

    if (r == -1)
        return -errno;

    /* Bail out now if already set/clear. */
    if (!!(r & FD_CLOEXEC) == !!set)
        return 0;

    if (set)
        flags = r | FD_CLOEXEC;
    else
        flags = r & ~FD_CLOEXEC;

    do
        r = fcntl(fd, F_SETFD, flags);
    while (r == -1 && errno == EINTR);

    if (r)
        return -errno;

    return 0;
}

#endif /* defined(__linux__) || defined(__FreeBSD__) || defined(__APPLE__) || \
          defined(_AIX) || defined(__DragonFly__) */

/* This function is not execve-safe, there is a race window
 * between the call to dup() and fcntl(FD_CLOEXEC).
 */
int uv__dup(int fd)
{
    int err;

    fd = dup(fd);

    if (fd == -1)
        return -errno;

    err = uv__cloexec(fd, 1);
    if (err) {
        uv__close(fd);
        return err;
    }

    return fd;
}

ssize_t uv__recvmsg(int fd, struct msghdr* msg, int flags)
{
    struct cmsghdr* cmsg;
    ssize_t rc;
    int* pfd;
    int* end;
#if defined(__linux__)
    static int no_msg_cmsg_cloexec;
    if (no_msg_cmsg_cloexec == 0) {
        rc = recvmsg(fd, msg, flags | 0x40000000); /* MSG_CMSG_CLOEXEC */
        if (rc != -1)
            return rc;
        if (errno != EINVAL)
            return -errno;
        rc = recvmsg(fd, msg, flags);
        if (rc == -1)
            return -errno;
        no_msg_cmsg_cloexec = 1;
    } else {
        rc = recvmsg(fd, msg, flags);
    }
#else
    rc = recvmsg(fd, msg, flags);
#endif
    if (rc == -1)
        return -errno;
    if (msg->msg_controllen == 0)
        return rc;
    for (cmsg = CMSG_FIRSTHDR(msg); cmsg != NULL; cmsg = CMSG_NXTHDR(msg, cmsg))
        if (cmsg->cmsg_type == SCM_RIGHTS)
            for (pfd = (int*)CMSG_DATA(cmsg),
                end = (int*)((char*)cmsg + cmsg->cmsg_len);
                 pfd < end;
                 pfd += 1)
                uv__cloexec(*pfd, 1);
    return rc;
}

int uv_cwd(char* buffer, size_t* size)
{
    if (buffer == NULL || size == NULL)
        return -EINVAL;

    if (getcwd(buffer, *size) == NULL)
        return -errno;

    *size = strlen(buffer);
    if (*size > 1 && buffer[*size - 1] == '/') {
        buffer[*size - 1] = '\0';
        (*size)--;
    }

    return 0;
}

int uv_chdir(const char* dir)
{
    if (chdir(dir))
        return -errno;

    return 0;
}

void uv_disable_stdio_inheritance(void)
{
    int fd;

    /* Set the CLOEXEC flag on all open descriptors. Unconditionally try the
   * first 16 file descriptors. After that, bail out after the first error.
   */
    for (fd = 0;; fd++)
        if (uv__cloexec(fd, 1) && fd > 15)
            break;
}

int uv_fileno(const uv_handle_t* handle, uv_os_fd_t* fd)
{
    int fd_out;

    switch (handle->type) {
    case UV_TCP:
    case UV_NAMED_PIPE:
    case UV_TTY:
        fd_out = uv__stream_fd((uv_stream_t*)handle);
        break;

    case UV_UDP:
        fd_out = ((uv_udp_t*)handle)->io_watcher.fd;
        break;

    case UV_POLL:
        fd_out = ((uv_poll_t*)handle)->io_watcher.fd;
        break;

    default:
        return -EINVAL;
    }

    if (uv__is_closing(handle) || fd_out == -1)
        return -EBADF;

    *fd = fd_out;
    return 0;
}

static int uv__run_pending(uv_loop_t* loop)
{
    QUEUE* q;
    QUEUE pq;
    uv__io_t* w;

    if (QUEUE_EMPTY(&loop->pending_queue))
        return 0;

    QUEUE_MOVE(&loop->pending_queue, &pq);

    while (!QUEUE_EMPTY(&pq)) {
        q = QUEUE_HEAD(&pq);
        QUEUE_REMOVE(q);
        QUEUE_INIT(q);
        w = QUEUE_DATA(q, uv__io_t, pending_queue);
        w->cb(loop, w, POLLOUT);
    }

    return 1;
}

static unsigned int next_power_of_two(unsigned int val)
{
    val -= 1;
    val |= val >> 1;
    val |= val >> 2;
    val |= val >> 4;
    val |= val >> 8;
    val |= val >> 16;
    val += 1;
    return val;
}

static void maybe_resize(uv_loop_t* loop, unsigned int len)
{
    uv__io_t** watchers;
    void* fake_watcher_list;
    void* fake_watcher_count;
    unsigned int nwatchers;
    unsigned int i;

    if (len <= loop->nwatchers)
        return;

    /* Preserve fake watcher list and count at the end of the watchers */
    if (loop->watchers != NULL) {
        fake_watcher_list = loop->watchers[loop->nwatchers];
        fake_watcher_count = loop->watchers[loop->nwatchers + 1];
    } else {
        fake_watcher_list = NULL;
        fake_watcher_count = NULL;
    }

    nwatchers = next_power_of_two(len + 2) - 2;
    watchers = uv__realloc(loop->watchers,
        (nwatchers + 2) * sizeof(loop->watchers[0]));

    if (watchers == NULL)
        abort();
    for (i = loop->nwatchers; i < nwatchers; i++)
        watchers[i] = NULL;
    watchers[nwatchers] = fake_watcher_list;
    watchers[nwatchers + 1] = fake_watcher_count;

    loop->watchers = watchers;
    loop->nwatchers = nwatchers;
}

void uv__io_init(uv__io_t* w, uv__io_cb cb, int fd)
{
    assert(cb != NULL);
    assert(fd >= -1);
    QUEUE_INIT(&w->pending_queue);
    QUEUE_INIT(&w->watcher_queue);
    w->cb = cb;
    w->fd = fd;
    w->events = 0;
    w->pevents = 0;

#if defined(UV_HAVE_KQUEUE)
    w->rcount = 0;
    w->wcount = 0;
#endif /* defined(UV_HAVE_KQUEUE) */
}

void uv__io_start(uv_loop_t* loop, uv__io_t* w, unsigned int events)
{
    assert(0 == (events & ~(POLLIN | POLLOUT | UV__POLLRDHUP)));
    assert(0 != events);
    assert(w->fd >= 0);
    assert(w->fd < INT_MAX);

    w->pevents |= events;
    maybe_resize(loop, w->fd + 1);

#if !defined(__sun)
    /* The event ports backend needs to rearm all file descriptors on each and
   * every tick of the event loop but the other backends allow us to
   * short-circuit here if the event mask is unchanged.
   */
    if (w->events == w->pevents) {
        if (w->events == 0 && !QUEUE_EMPTY(&w->watcher_queue)) {
            QUEUE_REMOVE(&w->watcher_queue);
            QUEUE_INIT(&w->watcher_queue);
        }
        return;
    }
#endif

    if (QUEUE_EMPTY(&w->watcher_queue))
        QUEUE_INSERT_TAIL(&loop->watcher_queue, &w->watcher_queue);

    if (loop->watchers[w->fd] == NULL) {
        loop->watchers[w->fd] = w;
        loop->nfds++;
    }
}

void uv__io_stop(uv_loop_t* loop, uv__io_t* w, unsigned int events)
{
    assert(0 == (events & ~(POLLIN | POLLOUT | UV__POLLRDHUP)));
    assert(0 != events);

    if (w->fd == -1)
        return;

    assert(w->fd >= 0);

    /* Happens when uv__io_stop() is called on a handle that was never started. */
    if ((unsigned)w->fd >= loop->nwatchers)
        return;

    w->pevents &= ~events;

    if (w->pevents == 0) {
        QUEUE_REMOVE(&w->watcher_queue);
        QUEUE_INIT(&w->watcher_queue);

        if (loop->watchers[w->fd] != NULL) {
            assert(loop->watchers[w->fd] == w);
            assert(loop->nfds > 0);
            loop->watchers[w->fd] = NULL;
            loop->nfds--;
            w->events = 0;
        }
    } else if (QUEUE_EMPTY(&w->watcher_queue))
        QUEUE_INSERT_TAIL(&loop->watcher_queue, &w->watcher_queue);
}

void uv__io_close(uv_loop_t* loop, uv__io_t* w)
{
    uv__io_stop(loop, w, POLLIN | POLLOUT | UV__POLLRDHUP);
    QUEUE_REMOVE(&w->pending_queue);

    /* Remove stale events for this file descriptor */
    uv__platform_invalidate_fd(loop, w->fd);
}

void uv__io_feed(uv_loop_t* loop, uv__io_t* w)
{
    if (QUEUE_EMPTY(&w->pending_queue))
        QUEUE_INSERT_TAIL(&loop->pending_queue, &w->pending_queue);
}

int uv__io_active(const uv__io_t* w, unsigned int events)
{
    assert(0 == (events & ~(POLLIN | POLLOUT | UV__POLLRDHUP)));
    assert(0 != events);
    return 0 != (w->pevents & events);
}

int uv_getrusage(uv_rusage_t* rusage)
{
    struct rusage usage;

    if (getrusage(RUSAGE_SELF, &usage))
        return -errno;

    rusage->ru_utime.tv_sec = usage.ru_utime.tv_sec;
    rusage->ru_utime.tv_usec = usage.ru_utime.tv_usec;

    rusage->ru_stime.tv_sec = usage.ru_stime.tv_sec;
    rusage->ru_stime.tv_usec = usage.ru_stime.tv_usec;

    rusage->ru_maxrss = usage.ru_maxrss;
    rusage->ru_ixrss = usage.ru_ixrss;
    rusage->ru_idrss = usage.ru_idrss;
    rusage->ru_isrss = usage.ru_isrss;
    rusage->ru_minflt = usage.ru_minflt;
    rusage->ru_majflt = usage.ru_majflt;
    rusage->ru_nswap = usage.ru_nswap;
    rusage->ru_inblock = usage.ru_inblock;
    rusage->ru_oublock = usage.ru_oublock;
    rusage->ru_msgsnd = usage.ru_msgsnd;
    rusage->ru_msgrcv = usage.ru_msgrcv;
    rusage->ru_nsignals = usage.ru_nsignals;
    rusage->ru_nvcsw = usage.ru_nvcsw;
    rusage->ru_nivcsw = usage.ru_nivcsw;

    return 0;
}

int uv__open_cloexec(const char* path, int flags)
{
    int err;
    int fd;

#if defined(UV__O_CLOEXEC)
    static int no_cloexec;

    if (!no_cloexec) {
        fd = open(path, flags | UV__O_CLOEXEC);
        if (fd != -1)
            return fd;

        if (errno != EINVAL)
            return -errno;

        /* O_CLOEXEC not supported. */
        no_cloexec = 1;
    }
#endif

    fd = open(path, flags);
    if (fd == -1)
        return -errno;

    err = uv__cloexec(fd, 1);
    if (err) {
        uv__close(fd);
        return err;
    }

    return fd;
}

int uv__dup2_cloexec(int oldfd, int newfd)
{
    int r;
#if defined(__FreeBSD__) && __FreeBSD__ >= 10
    r = dup3(oldfd, newfd, O_CLOEXEC);
    if (r == -1)
        return -errno;
    return r;
#elif defined(__FreeBSD__) && defined(F_DUP2FD_CLOEXEC)
    r = fcntl(oldfd, F_DUP2FD_CLOEXEC, newfd);
    if (r != -1)
        return r;
    if (errno != EINVAL)
        return -errno;
        /* Fall through. */
#elif defined(__linux__)
    static int no_dup3;
    if (!no_dup3) {
        do
            r = uv__dup3(oldfd, newfd, UV__O_CLOEXEC);
        while (r == -1 && errno == EBUSY);
        if (r != -1)
            return r;
        if (errno != ENOSYS)
            return -errno;
        /* Fall through. */
        no_dup3 = 1;
    }
#endif
    {
        int err;
        do
            r = dup2(oldfd, newfd);
#if defined(__linux__)
        while (r == -1 && errno == EBUSY);
#else
        while (0); /* Never retry. */
#endif

        if (r == -1)
            return -errno;

        err = uv__cloexec(newfd, 1);
        if (err) {
            uv__close(newfd);
            return err;
        }

        return r;
    }
}

int uv_os_homedir(char* buffer, size_t* size)
{
    uv_passwd_t pwd;
    char* buf;
    size_t len;
    int r;

    if (buffer == NULL || size == NULL || *size == 0)
        return -EINVAL;

    /* Check if the HOME environment variable is set first */
    buf = getenv("HOME");

    if (buf != NULL) {
        len = strlen(buf);

        if (len >= *size) {
            *size = len + 1;
            return -ENOBUFS;
        }

        memcpy(buffer, buf, len + 1);
        *size = len;

        return 0;
    }

    /* HOME is not set, so call uv__getpwuid_r() */
    r = uv__getpwuid_r(&pwd);

    if (r != 0) {
        return r;
    }

    len = strlen(pwd.homedir);

    if (len >= *size) {
        *size = len + 1;
        uv_os_free_passwd(&pwd);
        return -ENOBUFS;
    }

    memcpy(buffer, pwd.homedir, len + 1);
    *size = len;
    uv_os_free_passwd(&pwd);

    return 0;
}

int uv_os_tmpdir(char* buffer, size_t* size)
{
    const char* buf;
    size_t len;

    if (buffer == NULL || size == NULL || *size == 0)
        return -EINVAL;

#define CHECK_ENV_VAR(name)     \
    do {                        \
        buf = getenv(name);     \
        if (buf != NULL)        \
            goto return_buffer; \
    } while (0)

    /* Check the TMPDIR, TMP, TEMP, and TEMPDIR environment variables in order */
    CHECK_ENV_VAR("TMPDIR");
    CHECK_ENV_VAR("TMP");
    CHECK_ENV_VAR("TEMP");
    CHECK_ENV_VAR("TEMPDIR");

#undef CHECK_ENV_VAR

/* No temp environment variables defined */
#if defined(__ANDROID__)
    buf = "/data/local/tmp";
#else
    buf = "/tmp";
#endif

return_buffer:
    len = strlen(buf);

    if (len >= *size) {
        *size = len + 1;
        return -ENOBUFS;
    }

    /* The returned directory should not have a trailing slash. */
    if (len > 1 && buf[len - 1] == '/') {
        len--;
    }

    memcpy(buffer, buf, len + 1);
    buffer[len] = '\0';
    *size = len;

    return 0;
}

int uv__getpwuid_r(uv_passwd_t* pwd)
{
    struct passwd pw;
    struct passwd* result;
    char* buf;
    uid_t uid;
    size_t bufsize;
    size_t name_size;
    size_t homedir_size;
    size_t shell_size;
    long initsize;
    int r;
#if defined(__ANDROID_API__) && __ANDROID_API__ < 21
    int (*getpwuid_r)(uid_t, struct passwd*, char*, size_t, struct passwd**);

    getpwuid_r = dlsym(RTLD_DEFAULT, "getpwuid_r");
    if (getpwuid_r == NULL)
        return -ENOSYS;
#endif

    if (pwd == NULL)
        return -EINVAL;

    initsize = sysconf(_SC_GETPW_R_SIZE_MAX);

    if (initsize <= 0)
        bufsize = 4096;
    else
        bufsize = (size_t)initsize;

    uid = geteuid();
    buf = NULL;

    for (;;) {
        uv__free(buf);
        buf = uv__malloc(bufsize);

        if (buf == NULL)
            return -ENOMEM;

        r = getpwuid_r(uid, &pw, buf, bufsize, &result);

        if (r != ERANGE)
            break;

        bufsize *= 2;
    }

    if (r != 0) {
        uv__free(buf);
        return -r;
    }

    if (result == NULL) {
        uv__free(buf);
        return -ENOENT;
    }

    /* Allocate memory for the username, shell, and home directory */
    name_size = strlen(pw.pw_name) + 1;
    homedir_size = strlen(pw.pw_dir) + 1;
    shell_size = strlen(pw.pw_shell) + 1;
    pwd->username = uv__malloc(name_size + homedir_size + shell_size);

    if (pwd->username == NULL) {
        uv__free(buf);
        return -ENOMEM;
    }

    /* Copy the username */
    memcpy(pwd->username, pw.pw_name, name_size);

    /* Copy the home directory */
    pwd->homedir = pwd->username + name_size;
    memcpy(pwd->homedir, pw.pw_dir, homedir_size);

    /* Copy the shell */
    pwd->shell = pwd->homedir + homedir_size;
    memcpy(pwd->shell, pw.pw_shell, shell_size);

    /* Copy the uid and gid */
    pwd->uid = pw.pw_uid;
    pwd->gid = pw.pw_gid;

    uv__free(buf);

    return 0;
}

void uv_os_free_passwd(uv_passwd_t* pwd)
{
    if (pwd == NULL)
        return;

    /*
    The memory for name, shell, and homedir are allocated in a single
    uv__malloc() call. The base of the pointer is stored in pwd->username, so
    that is the field that needs to be freed.
  */
    uv__free(pwd->username);
    pwd->username = NULL;
    pwd->shell = NULL;
    pwd->homedir = NULL;
}

int uv_os_get_passwd(uv_passwd_t* pwd)
{
    return uv__getpwuid_r(pwd);
}
